DISCUSSION
This retrospective cross-sectional study found that patients diagnosed with CLE, who underwent surgical lobectomy, were symptomatic compared with the patients with conservative follow-up and those among the former who were diagnosed in the neonatal and early infancy period. The most common symptoms of the patients who underwent lobectomy at presentation were respiratory distress, tachypnea, and retraction. The most common symptom of the patients who were conservatively followed up was coughing. As with studies in the literature, our study observed that the most commonly involved lobes are the left upper and right middle lobes (5-8,11). The CLE is currently defined as a rare congenital airway malformation characterized by lobar hyperinflation that causes respiratory distress in the neonatal and infancy period. Obstruction in bronchial structures, increased aeration, compression atelectasis in adjacent tissues, and mediastinal shift are observed in symptomatic patients who are diagnosed within the first 6 months, mostly during the first postnatal days (24). Early diagnosis (fetal ultrasound, etc.) is important because tension pneumothorax can occur in these patients when respiratory distress develops with the first postnatal inspiration and when positive pressure ventilation is applied (25).
In our study, only two patients were diagnosed with fetal ultrasonography, whose widespread use has resulted in more frequent diagnoses of congenital pulmonary malformations (CPM). A multicenter retrospective study in 2019 examined data from 506 patients with CPM and observed CLE in 53 patients (10.3%) (26). The diagnosis of CPM without CLE has been shown to be significantly more frequent with fetal ultrasonography than with CLE, a result that has been attributed to the nonspecific echogenicity and rarer occurrence of CLE in fetal ultrasonography (26-28). Asymptomatic CLE with no mediastinal shift or atelectasis is diagnosed late. When diagnosed, this condition is mostly conservatively treated (29-30). CLE can go unnoticed in follow-up ultrasounds and, as it progresses, can sometimes lead to severe respiratory distress at birth (30). The presence of mediastinal shift and atelectasis in AR at birth has been correlated to respiratory distress and the need for neonatal intensive care during the neonatal period. Ten percent of patients with CLE and severe symptoms undergo surgical lobectomy during the neonatal period, mostly in the first week postpartum (27,28). Given that our study was retrospective, detailed fetal ultrasounds were not available for all of the conservatively followed up patients; however, the patients with an incidental diagnosis who were attended by a perinatologist were followed up.
In our study, CLE occurred within a wide age range, from the neonatal period to 17 years of age. In recent years, CLE has been shown to have a wide range of possible symptoms, from minimal pulmonary symptoms to respiratory failure in the neonatal period (6,13,26). These differences can vary depending on the lobar and segmental location of the CLE (26,31). There are reports in the literature of patients diagnosed with incidental segmental CLE at the age of 15 days who had a chest tube inserted with the pre-diagnosis of pneumothorax during the neonatal period and were subsequently diagnosed with CLE (8,32).
In our study, two patients with CLE were diagnosed incidentally in the imaging performed for other reasons, and four patients were diagnosed in the imaging performed for suspected foreign body aspiration and in the FB imaging. A study reported on a patient who was examined with a pre-diagnosis of CLE at the age of 48 days and was found to have foreign body aspiration; there was also a case report of a patient with suspected foreign body aspiration, who was diagnosed with CLE at the age of 15 years (15,33).
In our study, left upper lobe involvement was more common in the surgical group than in the conservatively treated group; however, the difference was not statistically significant. CLE with left upper lobe involvement is more symptomatic and more frequently requires surgery. There are publications showing that patients with right middle lobe CLE are generally asymptomatic and are conservatively treated; however, this might be due to the higher frequency of left upper lobe CLE (34-36).
In line with studies in the literature, the pulmonary symptoms and CLE-related imaging findings in our study regressed during the conservative follow-up. Many studies have shown no lung infection or malignant transformation during conservative follow-up (13,34-36). In the patients who underwent surgery, alveolar emphysema was the most common finding in the pathology specimens, with half of the specimens presenting cartilage hypoplasia. In the literature, emphysematous changes are the most common pathology findings, and accompanying cartilage hypoplasia has less frequently been reported (36).
In our study, the rate of CHD and other accompanying diseases was 15%, which is consistent with studies showing that the incidence of CHD varies between 6% and 24% in patients with CLE (14,37,38).
The limitations of our study were: 1) the results of the fetal ultrasounds could not be obtained for all patients due to the study’s retrospective design; 2) the patients were followed up with other diagnoses because our hospital is a reference center; and 3) the delay before the diagnosis was relatively prolonged, especially in the patients who underwent surgery. Due to technical issues (e.g., performing spirometry in patients too young to cooperate), detailed pulmonary function tests such as impulse oscillometry could not be performed on all patients.
In conclusion, we observed that respiratory distress and mediastinal shift were more prominent in patients who underwent surgery with a diagnosis of CLE compared with patients who were conservatively followed up. We also observed that those who underwent surgery were diagnosed at an earlier age. Clinicians should consider performing a detailed anamnesis for patients with unresolved respiratory symptoms and unilateral or bilateral increased ventilation. Clinicians should also perform appropriate imaging tests and examinations (including FB) and should consider CLE in the diagnosis.